forget dropping $200 on one of those backpacks that allows you to hookup a cdplayer or something similar to blast music around the streets at 2am. you can make one yourself on the cheap! you’ll need an old boombox very similar to the one he has (it’s pretty straightforward) and a backpack you don’t mind tearing up a bit.
“mobius9″ gutted the entire boombox, then secured the speakers on plexiglass or something similar and even added a subwoofer he found lying around. it took quite awhile but the result is really cool.